In the drilling of oil and gas wells, various techniques for providing communication between a surface system and equipment in a borehole have been devised. Such communication is generally directed to providing control over the function of a downhole tool from the surface, and/or providing information indicative of downhole conditions (e.g., borehole environmental conditions, tool conditions, etc.) to the surface. Exemplary downhole communication techniques include modulation of drilling fluid (mud) pressure or flow rate, communication via wireline or wired drill pipe, electromagnetic communication, acoustic communication, etc. Each technique has its advantages and disadvantages. For example, the mud column provides a convenient medium for communication because the circulation of drilling fluid is needed to clean and maintain pressure in the borehole. However, mud pressure modulation can be unreliable because the drilling fluid is susceptible to pressure changes not induced by a modulator of the communication system (e.g., changes in formation pressure). Mud flowrate and pressure are also affected when communication tools are run below a pulsing device, such as a MWD or mud motor, this can make signal decoding less reliable and more complex. Mud pulses also get degraded as the distance from the surface to the tool increases requiring the use of increasing time intervals between commands. Current systems also require the use of many different codes to send specific downlinks to the tool.